The present invention relates generally to a gear shift for a manual transmission of a motorized vehicle and, more specifically, to a gear shift tower assembly having a spring-biased centering mechanism for positively positioning the shift lever in a desired location.
Conventional manual transmissions are equipped with a gear shift assembly which permits a vehicle operator to selectively shift between various forward ratio gears and a reverse gear. The gear shift assembly includes a tower housing secured to an exterior surface of the transmission casing and a gear shift lever that is operably coupled to a socket and shift rail in the transmission. Typically, the gear shift assembly has a standard shift pattern such that the shift lever is movable along a neutral cross-over path to a plurality of preselected gate positions. Each gate position defines a linear shift plane for a pair of ratio gears. Most commonly, the gate position located at one end of the neutral cross-over path defines the linear shift plane between the first and second forward gears, or the 1-2 shift plane, the gate position located in the center of the neutral cross-over path defines the shift plane between the third and fourth forward gears, or the 3-4 shift plane, and the gate position at the opposite end of the neutral cross-over path defines a shift plane between the fifth forward ratio gear and the reverse gear position, or the 5-R shift plane.
Gear shift levers incorporate various mechanisms to positively position the shift lever in a desired position. For example, a spring member may be operably connected to the gear shift lever of the gear shift tower assembly to bias the shift lever. As such, the spring mechanism generates a return force that acts directly on the shift lever for biasing the shift lever to a center position. However, gear shift assemblies of this type have proven to be difficult to provide a smoothly operating mechanism or to provide a substantially constant centering force.